Hammer broke again

And this time there wasn't even an SDK "update" involved. It just sorta randomly happened.

I can no longer load up a map with any real substance in it and still navigate around the 3D view with any sort of precision. Holding down W jumps me forward at about 1fps, and slowly tapping it for finer control doesn't cause any movement at all.

OK, I have determined a few things: First, telling the SDK launcher to refresh the SDK content and reset the game configurations doesn't fix the problem. Secondly, this seems to only happen with TF2 maps. I can literally launch the TF2 version of Hammer and load up a decompiled Half-Life 2 map, and it'll be fine. It's almost as if there's something about TF2 maps in particular that cause performance issues. But that's crazy, right?